The present invention relates to navigation systems, and is particularly applicable to navigation systems for land vehicles. Navigation systems for use in shipping, air and space travel are well known and their benefit is indisputable. More recently, navigation systems for overland travel have met with increasing interest and homing systems for travel on motorways and city road systems have been proposed.
An electronic traffic pilot for motorists is described in an article in the German magazine "Funknavigation", issue No. 4 of 1983, entitled EVA-Ortungs-und Navigations system fur Landfahrzeuge, by Ernst P. Neukirchner, Otmar Pilsak, and Dietmar Schlogl. The basic system includes a driver communication system in which the starting point and the desired destination are entered, and direction recommendations issued; a route search system, which computes the optimum route, based on the starting point and destination entered, by accessing a digital illustration of the road system; a locating system which continuously updates the actual position during the journey and a navigation system, which makes a comparison of the set route and the actual route and, in the event of any disparity, causes the route search system to determine a new optimum route from the actual position. This last feature makes the homing always optimal, regardless of whether or not the directional recommendations are followed.
The known system requires a very large data handling capability and is hence complex and expensive to produce. Using this system the driver simply has to enter his desired destination and the navigation system will guide him there, for example using commands output in synthetic language. Thus, this system requires the minimum of activity on the part of the driver. However, a simpler system would be desirable from the standpoint of cost and large-scale production.